Evaluating environmentally weighted recycling efficiency of a technology: discussion of methodology and application on a case-study

Since the introduction of the European Commission’s Critical Raw Materials list in 2011, the evaluation of recycling technologies has gained strategic importance from the dual perspective of environmental preservation and resource recovery potential. In particular, Life Cycle Assessment (LCA) has become a key methodological tool for analyzing recycling processes involving metal scraps, waste electrical and electronic equipment, and industrial residues. However, from a methodological standpoint, the inherent multifunctionality of recovery technologies, acting both as waste treatment systems and as providers of secondary raw materials, poses significant challenges for impact assessment. This work examines an integrated approach that combines LCA with synthetic recyclability indexes to enable a more effective evaluation of the environmental and resource-efficiency performance of a real metal recycling facility. These indexes, originally developed to assess the recyclability of electronic products, are adapted and applied here to separate calculation of the environmental burdens and benefits associated with the recycling process. The methodology focuses on critical parameters such as conservation of natural resources, feedstock characteristics, and the composition of output materials. The results highlight some key methodological challenges, including the treatment of multifunctionality, the modelling of avoided impacts from secondary metal substitution, and the influence of feedstock variability. In particular the relative mass fraction of precious material in the feedstock seems particularly relevant in addressing both environmental impact and scarcity indexes, and there is a need to calibrate the feedstock composition to a defined treatment time frame when assessing the performance of a specific recycling technology. The findings evidence the need for harmonized allocation rules and standardized frameworks for quantifying environmental impacts and benefits, which are essential for improving the comparability and robustness of LCA-based evaluations of recycling technologies.